In medicine, ultrasonic technology has become established in diagnostics as well as in therapy. Ultrasound is utilized in diagnostics in laparoscopy and angioplasty in addition to the known extracorporeal image yielding methods. For example, plaque in arteries is diagnosed with an ultrasonic catheter in the high frequency ultrasonic range between 5 MHz and 40 MHz.
Lower frequency energy ultrasound between 20 and 40 kHz is used for cutting tissue in open surgery. For example, the so-called CUSA-technique (Cavitation Ultrasonics Surgical Aspirator) is preferably used for the excision of brain and liver tumors in neurosurgery and in general surgery. The advantage of the CUSA-method is seen in the tissue-differentiating cutting. This is so because the soft tumor cells can be separated without much blood loss while the elastic organ supplying vessels and nerves are spared.
However, up until now, there is no endoscopically useable applicator having an amplitude adequate for cutting tissue. The metal sound conductors used until now have losses which are too high with the result of an intense development of heat in the sound conductor which is unwanted for endoscopic applications. Metal hollow waveguides and corresponding applicators for ultrasonic angioplasty are known and are, for example, described in the dissertation paper of U. Stumpf "Die Erzeugung und Ubertragung von Ultraschalldehnwellen hoher Energiedichten in flexiblen Wellenleitern im 20 kHz-Bereich fur therapeutische Anwendungen" (RWTH Aachen, 1978).
It is known from International patent application publication no. WO 87/01269 to utilize flexible glass fibers as sound conductors for an image-forming ultrasonic diagnostic method. In this method, however, only relatively low sound energies are transmitted via the waveguide.
From the older, but yet not published patent application DE 41 15 447 as well as patent application DE 41 03 145, it is known to transmit ultrasound, for example, with the aid of quartz glass fibers into the interior of the body, first to monitor the degree of destruction of the concrements during the extracorporeal shock wave lithotripsy and, on the other hand, for example, for the medical endosonography. In both cases, however, likewise only a relatively low sound energy is transmitted by the quartz glass waveguide. Insofar as the transmission of optical signals or light energy is touched upon in the above-mentioned DE 41 03 145, only low radiation intensities are concerned here as they are required, for example, for illuminating the object sighted by the endoscope.
Furthermore, it is known to transmit high intensity light or laser radiation via optical light waveguides, especially also made of quartz glass, and to use this radiation, for example, with the aid of endoscopes and catheters for cutting and coagulating tissue in the interior of the body.
The two methods touched upon, the ultrasound therapy according to the, for example, CUSA-technique and the laser surgery have previously, however, been alternatively used in dependence upon whether the one or the other method is better suited for the desired purpose. A combination of both methods is not known up to now.
From DE-OS 39 35 528, it is known to transmit the radiation of a pulsed laser for the treatment of biological tissue and, at the same time, to conduct back the shock waves occurring distally during the treatment via the quartz glass fibers to a pressure receiver coupled proximally to the fiber. This known system is, however, neither suited for ultrasound therapy nor for the ultrasound diagnosis.